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1.
Environ Res ; 262(Pt 1): 119798, 2024 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-39151556

RESUMEN

Algal blooms threaten water quality and ecosystem stability in aquatic habitats globally, yet dynamics regulating phytoplankton community assembly, the basis of blooms, remain poorly characterized in small water bodies. Here, we employed high-throughput sequencing to analyze drivers structuring phytoplankton across a trophic gradient of 10 small water bodies over 12 consecutive months. Cyanobacteria and Chlorophyta were identified as potential seed banks priming blooms. Temporal variation in community composition was muted in nutrient-limited waters given Cyanobacteria dominance. Environmental factors and interspecific relationships jointly governed temporal phytoplankton dynamics. Phytoplankton, exhibiting greater sensitivity, responded more rapidly than bacterioplankton to environmental and biological fluctuations. This research provides a robust bench mark characterizing planktonic successional trajectories across small water bodies varying in trophic status. Results reinforce ecological mechanisms underpinning biological control strategies to mitigate algal proliferation and inform water quality management of these ubiquitous aquatic ecosystems.

2.
J Environ Manage ; 370: 122485, 2024 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-39278018

RESUMEN

Despite the rapid development of research on aquatic environment microbiota, limited attention has been paid to exploring the complex interactions between microbial communities and aquatic environments. Particularly, the mechanisms underlying fish diseases based on such dynamic interactions remain unknown. This study aimed to address the gap by conducting microbiome and co-occurrence network analyses on the typical freshwater aquaculture systems. High-throughput 16S rRNA gene sequencing results revealed significant differences in the microbiota between the disease and healthy groups. Notably, disease mortality varied consistently with the gradient of relative abundance of Proteobacteria (intestine, R2 = 0.46, p < 0.05) and Cyanobacteria (gill, R2 = 0.67, p < 0.01), indicating their potential use as diagnostic criteria. Furthermore, the elevated hepatosomatic index, NO3-N, COD and TC (sediment) were directly correlated with diseases (r > 0.54, p < 0.01). Mean concentrations of NO3-N, COD and TC were elevated by 78.87%, 25.63% and 44.2%, respectively, in ponds where diseases occurred. Quantitative analysis (qPCR) revealed that Aeromonas sobria infected hosts through a potential pathway of "sediment (4.4 × 105 copy number/g)-water (1.1 × 103 copy number/mL)-intestine (1.2 × 106 copy number/g)". Similarly, the potential route for Aeromonas veronii was sediment (4.9 × 106 copy number/g) to gill (5.1 × 105 copy number/g). Additionally, the complexity of microbial networks in the intestine, water, and sediment was significantly lower in the disease group, although no similar phenomenon was observed in the gill microbial network. In summary, these findings reveal that elevated concentrations of crucial environmental factors disrupt the linkages within microbiota, fostering the growth of opportunistic bacteria capable of colonizing fish gut or gills. This offers new insights into potential mechanisms by which environmental factors cause disease in fish.

3.
J Environ Sci (China) ; 146: 3-14, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38969459

RESUMEN

Bacillus velezensis M3-1 strain isolated from the sediment of Myriophyllum aquatium constructed wetlands was found to efficiently convert NO3--N to NO2--N, and the requirements for carbon source addition were not very rigorous. This work demonstrates, for the first time, the feasibility of using the synergy of anammox and Bacillus velezensis M3-1 microorganisms for nitrogen removal. In this study, the possibility of M3-1 that converted NO3--N produced by anammox to NO2--N was verified in an anaerobic reactor. The NO3--N reduction ability of M3-1 and denitrifying bacteria in coupling system was investigated under different C/N conditions, and it was found that M3-1 used carbon sources preferentially over denitrifying bacteria. By adjusting the ratio of NH4+-N to NO2--N, it was found that the NO2--N converted from NO3--N by M3-1 participated in the original anammox.The nitrogen removal efficacy (NRE) of the coupled system was increased by 12.1%, compared to the control group anammox system at C/N = 2:1. Functional gene indicated that it might be a nitrate reducing bacterium.This study shows that the nitrate reduction rate achieved by the Bacillus velezensis M3-1 can be high enough for removing nitrate produced by anammox process, which would enable improve nitrogen removal from wastewater.


Asunto(s)
Amoníaco , Bacillus , Nitratos , Nitrógeno , Oxidación-Reducción , Bacillus/metabolismo , Nitrógeno/metabolismo , Nitratos/metabolismo , Amoníaco/metabolismo , Anaerobiosis , Eliminación de Residuos Líquidos/métodos , Desnitrificación
4.
Environ Res ; 239(Pt 1): 117245, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37774999

RESUMEN

The squeezed liquid from fruit and vegetable waste (LW) presents a unique wastewater challenge, marked by recalcitrance in treatment and amplified design risks with the application of conventional processes. Following coagulation of the squeezed liquid, the majority of particulate matter precipitates. The resulting precipitated floc (LWF) is reclaimed and subsequently utilized for the synthesis of biochar. The present study primarily explores the viability of repurposing LWF as biochar to enhance soil quality and mitigate N2O emissions. Findings indicate that the introduction of a 2% proportion of LWFB led to a remarkable 99.5% reduction in total N2O emissions in contrast to LWF. Concurrently, LWFB substantially enhanced nutrients content by elevating soil organic carbon (SOC) and nitrogen levels. Utilizing high-throughput sequencing in conjunction with qPCR, the investigation unveiled that the porous structure and substantial specific surface area of LWFB potentially fostered microbial adhesion and heightened diversity within the soil microbial community. Furthermore, LWFB notably diminished the relative abundance of AOB (Nitrosospira, Nitrosomonas), and NOB (Candidatus_Nitrotoga), thereby curbing the conversion of NH4+ into NO3-. The pronounced elevation in nosZ abundance implies that LWFB holds the potential to mitigate N2O emissions through a conversion to N2.


Asunto(s)
Microbiota , Suelo , Suelo/química , Carbono , Verduras , Frutas/química , Óxido Nitroso , Microbiología del Suelo
5.
Int J Mol Sci ; 24(5)2023 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-36902302

RESUMEN

Through excellent absorption and transformation, the macrophyte Myriophyllum (M.) aquaticum can considerably remove phosphorus from wastewater. The results of changes in growth rate, chlorophyll content, and roots number and length showed that M. aquaticum could cope better with high phosphorus stress compared with low phosphorus stress. Transcriptome and differentially expressed genes (DEGs) analyses revealed that, when exposed to phosphorus stresses at various concentrations, the roots were more active than the leaves, with more DEGs regulated. M. aquaticum also showed different gene expression and pathway regulatory patterns when exposed to low phosphorus and high phosphorus stresses. M. aquaticum's capacity to cope with phosphorus stress was maybe due to its improved ability to regulate metabolic pathways such as photosynthesis, oxidative stress reduction, phosphorus metabolism, signal transduction, secondary metabolites biosynthesis, and energy metabolism. In general, M. aquaticum has a complex and interconnected regulatory network that deals efficiently with phosphorus stress to varying degrees. This is the first time that the mechanisms of M. aquaticum in sustaining phosphorus stress have been fully examined at the transcriptome level using high-throughput sequencing analysis, which may indicate the direction of follow-up research and have some guiding value for its future applications.


Asunto(s)
Saxifragales , Transcriptoma , Fósforo/metabolismo , Nitrógeno/metabolismo , Aguas Residuales
6.
J Environ Manage ; 330: 117033, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36603247

RESUMEN

Anaerobic digestion (AD) of wasted activated sludge from wastewater plants is recognized as an effective method to reclaim energy in the form of methane. AD performance has been enhanced by coupling various pretreatments that impact energy conversion from sludge. This paper mainly reviewed the development of pretreatments based on different technologies reported in recent years and evaluated their energy benefit. Significant increases in methane yield are generally obtained in AD with pretreatments demanding energy input, including thermal- and ultrasound-based methods. However, these energy-intense pretreatments usually gained negative energy benefit that the increase in methane yield consumed extra energy input. The unbalanced relationship counts against the goal of energy reclamation from sludge. Combined pretreatment consisting of multiple technologies normally outcompetes the single pretreatment, and the combination of energy-intense methods and chemicals potentially reduces energy input and simultaneously ensure high methane yield. For determining whether the energy reclamation from sludge via AD contribute to mitigating global warming, integrating greenhouse gas emission into the evaluation system of pretreated AD is further warranted.


Asunto(s)
Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Anaerobiosis , Eliminación de Residuos Líquidos/métodos , Metano , Aguas Residuales , Reactores Biológicos
7.
J Environ Manage ; 329: 117052, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36535139

RESUMEN

Effluents from wastewater treatment plants (WWTPs) is the main source of pollution in rivers in developing countries. In this case study, three bypass ecological treatment systems along urban rivers achieved high removal efficiencies for chemical oxygen demand (COD; 55.7-64.0%), ammonium N (NH4+-N; 63.1-89.4%) and total phosphorous (TP; 27.6-76.7%). 16 S rRNA gene sequencing analysis confirmed that Proteobacteria was the main bacterial phylum (44.4%) in the ecological treatment system, and members were enriched significantly in the non-aeration area (59.3%). The relative abundance of Nitrospirae was highest in the inflow area (25.0%), but restrained in the non-aeration area (5.7%). 18 S rRNA gene annotation results indicated that phylum Rotifer was gradually inhibited with the direction of water flow and diffusion, while phylum Rhodophyta displayed the opposite trend. After implementation of bypass ecological treatment systems, receiving rivers were improved significantly from Grade Ⅴ to Ⅳ, and the biodiversity of zooplankton, zoobenthos and fish communities was greatly improved.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Calidad del Agua , Aguas Residuales , Ecosistema , Ríos/microbiología , Bacterias/genética , Purificación del Agua/métodos , China , Contaminantes Químicos del Agua/análisis
8.
J Environ Manage ; 338: 117836, 2023 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-37011530

RESUMEN

The slow startup is the major obstacle to the application of anaerobic ammonium oxidation (anammox) process in mainstream wastewater treatment. Extracellular polymeric substances (EPS) are one potential resource for stable anammox reactor operation. Response surface analysis was used to optimize the specific anammox activity (SAA) with the addition of EPS; SAA was maximum at a temperature of 35 °C and the EPS concentration of 4 mg/L. By comparing the nitrogen removal of anammox reactors with no EPS (R0), immobilized EPS (EPS-alginate beads) (R1), and liquid EPS (R2), we found that EPS-alginate beads significantly speed up the startup of anammox process and enable the start time to be shortened from 31 to 19 days. As a result of the higher MLVSS content, higher zeta potential, and lower SVI30, anammox granules of R1 exhibited a stronger capacity to aggregate. Moreover, EPS extracted from R1 had higher flocculation efficiencies than EPS derived from R0 and R2. Phylogenetic analysis of 16S rRNA genes revealed that the main anammox species in R1 is Kuenenia taxon. To clarify the relative significance of stochastic vs deterministic processes in the anammox community, neutral model and network analysis are employed. In R1, community assembly became more deterministic and stable than in other cultures. Our results show that EPS might inhibit heterotrophic denitrification and thereby promote anammox activity. This study suggested a quick start-up strategy for the anammox process based on resource recovery, which is helpful for environmentally sustainable and energy-efficient wastewater treatment.


Asunto(s)
Reactores Biológicos , Matriz Extracelular de Sustancias Poliméricas , Reactores Biológicos/microbiología , Filogenia , Oxidación Anaeróbica del Amoníaco , ARN Ribosómico 16S , Aguas del Alcantarillado , Oxidación-Reducción , Nitrógeno/farmacología , Desnitrificación , Anaerobiosis
9.
J Environ Sci (China) ; 127: 30-41, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36522062

RESUMEN

With the rapid expansion of livestock production, the amount of livestock wastewater accumulated rapidly. Lack of biodegradable organic matter makes denitrification of livestock wastewater after anaerobic digestion more difficult. In this study, Myriophyllum aquaticum constructed wetlands (CWs) with efficient nitrogen removal performance were established under different carbon/nitrogen (C/N) ratios. Analysis of community composition reveals the change of M. aquaticum CWs in microbial community structure with C/N ratios. The proportion of Proteobacteria which is one of the dominant phyla among denitrifier communities increased significantly under low C/N ratio conditions. Besides, to obtain cultivable denitrifier that could be added into CWs in situ, 33 strains belonging to phylum Proteobacteria were isolated from efficient M. aquaticum CWs, while the best-performing denitrification strain M3-1 was identified as Bacillus velezensis JT3-1 (GenBank No. CP032506.1). Redundancy analysis and quadratic models showed that C/N ratio had significant effects on disposal of nitrate (NO3--N) and the strains isolated could perform well in denitrification when C/N ratio is relatively low. In addition, they have relatively wide ranges of carbon sources, temperature and a high NO3- removal rate of 9.12 mg/(L·hr) at elevated concentrations of 800 mg/L nitrate. Thus, strains isolated from M. aquaticum CWs with low C/N ratio have a practical application value in the treatment of nitrate-containing wastewater. These denitrifying bacteria could be added to CWs to enhance nitrogen removal efficiency of CWs for livestock wastewater with low C/N ratio in the future.


Asunto(s)
Microbiota , Humedales , Nitrógeno/análisis , Aguas Residuales , Carbono , Desnitrificación , Nitratos/análisis , Eliminación de Residuos Líquidos , Proteobacteria
10.
Environ Res ; 210: 112957, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35167854

RESUMEN

Constructed wetlands (CWs) can remove nitrogen (N) through plant assimilation and microbial nitrification and denitrification, while it also releases large greenhouse gas nitrous oxide (N2O) into the atmosphere. However, N2O emissions and the underlying microbial mechanisms of CWs when treating high-strength wastewater have not been systematically surveyed. Here, the effect of three influent strengths on N2O emissions in a pilot-scale CW treatment of swine wastewater was determined and the underlying microbial mechanisms were explored. The results showed that the removal rates of ammonium (NH4+) and total nitrogen (TN) increased significantly with the increasing influent strengths, however, the ratio of N2O emission/TN removal rose by 1.5 times at the same time. Quantitation of microorganisms responsible for N-cycle in the sediment indicated that the abundance of ammonia-oxidizing bacteria (AOB) in high influent strengths (COD, 962.38 ± 3.05 mg/L; NH4+, 317.89 ± 4.24 mg/L) was 51.6-fold compared with that in low influent strengths (COD, 516.94 ± 4.18 mg/L; NH4+, 100.65 ± 2.65), and AOB gradually replaced ammonia-oxidizing archaea (AOA) to dominate ammonia oxidizers. Structural equation models demonstrated that NO2- accumulations promoted the ratio of AOB/AOA, which further led to an increase in the ratio of N2O emission/TN removal. It is worth noting both the N removal rates and N2O emissions increased with the increasing influent strength. To obtain reduced N2O emissions, pretreatment technology for strength reduction should be supplemented before high-strength wastewater enters the CWs. This study may shed new light on the sustainable operation and application of CWs.


Asunto(s)
Óxido Nitroso , Aguas Residuales , Amoníaco , Animales , Nitrógeno , Porcinos , Aguas Residuales/química , Humedales
11.
Can J Microbiol ; 66(3): 214-227, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32011910

RESUMEN

Increasing the use of nitrogen fertilizers in tea orchards has led to intense nitrous oxide (N2O) emissions. Foliar application of Paenibacillus polymyxa biofertilizer has been proven to be beneficial for organic tea production. In this study, tea yield and quality were significantly improved after application of P. polymyxa biofertilizer compared with the control but were not significantly different from chemical fertilizer treatments. However, the average N2O fluxes in tea fields treated with chemical fertilizers and biofertilizers (225 kg N·ha-1·year-1 for both) were 50.6-973.7 and 0.6-29.1 times higher than those in the control treatment, respectively. Pot experiments conducted to explore the mechanism of N2O reduction induced by P. polymyxa biofertilizer showed that applying P. polymyxa in addition to urea could reduce N2O fluxes by 36.5%-73.1%. Quantitative PCR analysis suggested that a significant increase in the quantity of nirK and nosZ genes was linked to the reduction of N2O, and high-throughput sequencing of nosZ revealed active and potentially efficient denitrifiers in different treatments. Our findings suggest that P. polymyxa biofertilizer is in line with the requirements of modern agriculture, which aims to increase product yield and quality while reducing negative environmental impacts.


Asunto(s)
Inoculantes Agrícolas/metabolismo , Camellia sinensis/microbiología , Fertilizantes/análisis , Óxido Nitroso/metabolismo , Paenibacillus polymyxa/metabolismo , Microbiología del Suelo , Agricultura , Camellia sinensis/crecimiento & desarrollo , Desnitrificación , Óxido Nitroso/análisis , Suelo/química , Urea/metabolismo
12.
Int J Mol Sci ; 20(7)2019 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-30934901

RESUMEN

Massively input and accumulated ammonium is one of the main causes of eutrophication in aquatic ecosystems, which severely deteriorates water quality. Previous studies showed that one of the commonly used macrophytes, Myriophyllum aquaticum, was capable of not only withstanding ammonium of high concentration, but also efficiently assimilating extracellular ammonium to constitutive amino acids and proteins. However, the genetic mechanism regulating such efficient nitrogen metabolism in M. aquaticum is still poorly understood. Therefore, RNA-based analysis was performed in this study to understand the ammonium regulatory mechanism in M. aquaticum in response to various concentrations of ammonium. A total of 7721 genes were differentially expressed, of which those related to nitrogen-transport, assimilation, and remobilization were highly-regulated in response to various concentrations of ammonium. We have also identified transcription factors and protein kinases that were rapidly induced in response to ammonium, which suggests their involvement in ammonium-mediated signalling. Meanwhile, secondary metabolism including phenolics and anthocyanins biosynthesis was also activated in response to various concentrations of ammonium, especially at high ammonium concentrations. These results proposed a complex physiological and genetic regulation network related to nitrogen, carbohydrate, transcription factors, and secondary metabolism for nitrogen use efficiency in M. aquaticum.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Redes Reguladoras de Genes , Genes de Plantas , Nitrógeno/metabolismo , Saxifragales/genética , Análisis de Secuencia de ARN , Transcriptoma/genética , Aminoácidos/análisis , Compuestos de Amonio/farmacología , Metabolismo de los Hidratos de Carbono/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Ontología de Genes , Familia de Multigenes , Fenotipo , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/metabolismo , Reproducibilidad de los Resultados , Factores de Transcripción/metabolismo
13.
ACS Omega ; 9(37): 39259-39276, 2024 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-39310150

RESUMEN

The high viscosity of heavy crude oil has been an obstacle to its safe production and economic transportation. In this work, a screened emulsified viscosity reducer system is conducted. Experimental results demonstrate that the most effective viscosity reducing agent comprises sodium oleate (NaOl) and cocamidopropyl betaine (CAB-35) in a ratio of 1:2, achieving a viscosity reduction rate of 94.65%. Additionally, the interfacial tension between oil and water decreases from 27 to 4 mN/m with 0.1 mass % TEOA and NaOH in a 1:1 ratio. The oil droplet size is uniformly distributed with D mean is 14 µm and D 50 is 11 µm. Droplets flocculate as the salinity increases to 0.2 mol/L, which corresponds to the apparent increase of viscosity. The adsorption of long alkyl chain lipophilic groups on surfactant molecules at the oil-water interface and the water film alters the wettability of pipe steel to water-wet, further enhancing the application of emulsification and viscosity reduction effects. The primary mechanism behind the viscosity reduction in emulsification is attributed to strong electrostatic interactions stemming from molecular electrostatic potential distributions.

14.
Bioresour Technol ; 408: 131207, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39098354

RESUMEN

This study proposes an innovative strategy for achieving PN in synthetic domestic wastewater by side-stream sludge treatment using sulfide as the sole control factor. By conducting controllable batch experiments and response surface analysis, optimal sulfide treatment conditions were firstly determined as 90 mg/L of sulfide, 7.5 of pH, 100 rpm of rotation and 12 h of treatment time. After treatment, half of ammonia oxidizing bacteria (AOB) activity remained, but nitrite oxidizing bacteria (NOB) activity was barely detected. Nitrite accumulation rate of long-term running PN steadily reached 83.9 % with 99.1 % of ammonia removal efficiency. Sulfide treatment increased community diversity and facilitated stability of microbiota functioning with PN phenotype, which might be sustained by the positive correlation between ammonia oxidation gene (amoA) and sulfur oxidation gene (soxB). Correspondingly, the network analysis identified the keystone microbial taxa of persistent PN microbiota as Nitrosomonas, Thauera, Truepera, Defluviimonas and Sulitalea in the later stage of long-term reactor.


Asunto(s)
Amoníaco , Bacterias , Nitrificación , Aguas del Alcantarillado , Sulfuros , Sulfuros/química , Aguas del Alcantarillado/microbiología , Bacterias/metabolismo , Bacterias/genética , Amoníaco/metabolismo , Reactores Biológicos/microbiología , Nitritos/metabolismo , Purificación del Agua/métodos , Microbiota
15.
J Hazard Mater ; 475: 134934, 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-38889463

RESUMEN

Emerging pollutants (EPs) are prevalent in aquatic environments globally. Researchers strive to understand their occurrence and behavior prior to their release into the environment. In this study, we examined five wastewater treatment plants (WWTPs), collected 50 wastewater samples and 10 sludge samples. We explored the sources and destinations of phthalic acid esters (PAEs) within these WWTPs using mass balance equations. Wastewater treatment diminished the frequency and concentration of PAEs, and decreased the fraction of short-chain PAEs. We confirmed the increased concentration of PAEs post-primary treatment and modified the mass balance equation. Calculations suggest that weaker "the mix" in winter than in summer and stronger sedimentation in winter than in summer resulted in high efficiency of PAEs removal by winter wastewater treatment. The mass flux of biodegradation was influenced by the combination of biodegradation efficiency and the strength of the particular type of PAEs collected, with no seasonal differences. Mass fluxes for sludge sedimentation were mainly influenced by season and were higher in winter than in summer. This study enhances our understanding of emerging pollutants in manual treatment facilities and offers insights for optimizing wastewater treatment methods for water professionals.


Asunto(s)
Ésteres , Ácidos Ftálicos , Estaciones del Año , Eliminación de Residuos Líquidos , Aguas Residuales , Contaminantes Químicos del Agua , Ácidos Ftálicos/análisis , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química , Aguas Residuales/química , Ésteres/análisis , Ésteres/química , Eliminación de Residuos Líquidos/métodos , Aguas del Alcantarillado/química , Biodegradación Ambiental , Purificación del Agua/métodos
16.
Water Res ; 249: 120949, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38070348

RESUMEN

The start-up and stable operation of partial nitritation-anammox (PN/A) treatment of mature landfill leachate (MLL) still face challenges. This study developed an innovative staged pilot-scale PN/A system to enhance nitrogen removal from MLL. The staged process included a PN unit, an anammox upflow enhanced internal circulation biofilm (UEICB) reactor, and a post-biofilm unit. Rapid start-up of the continuous flow PN process (full-concentration MLL) was achieved within 35 days by controlling dissolved oxygen and leveraging free ammonia and free nitrous acid to selectively suppress nitrite-oxidizing bacteria (NOB). The UEICB was equipped with an annular flow agitator combined with the enhanced internal circulation device of the guide tube, which achieved an efficient enrichment of Candidatus Kuenenia in the biofilm (relative abundance of 33.4 %). The nitrogen removal alliance formed by the salt-tolerant anammox bacterium (Candidatus Kuenenia) and denitrifying bacteria (unclassified SBR1031 and Denitratisoma) achieved efficient nitrogen removal of UEICB (total nitrogen removal percentage: 90.8 %) and at the same time effective treatment of the refractory organic matter (ROM). The dual membrane process of UEICB fixed biofilm combined with post-biofilm is effective in sludge retention, and can stably control the effluent suspended solids (SS) at a level of less than 5 mg/L. The post-biofilm unit ensured that effluent total nitrogen (TN) remained below the 40 mg/L discharge standard (98.5 % removal efficiency). Compared with conventional nitrification-denitrification systems, the staged PN/A process substantially reduced oxygen consumption, sludge production, CO2 emissions and carbon consumption by 22.8 %, 67.1 %, 87.1 % and 87.1 %, respectively. The 195-day stable operation marks the effective implementation of the innovative pilot-scale PN/A process in treating actual MLL. This study provides insights into strategies for rapid start-up, robust NOB suppression, and anammox biomass retention to advance the application of PN/A in high-ammonia low-carbon wastewater.


Asunto(s)
Desnitrificación , Contaminantes Químicos del Agua , Amoníaco , Nitritos , Nitrógeno , Aguas del Alcantarillado , Biomasa , Oxidación Anaeróbica del Amoníaco , Reactores Biológicos/microbiología , Oxidación-Reducción , Nitrificación , Bacterias , Carbono
17.
Front Bioeng Biotechnol ; 11: 1247711, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38094897

RESUMEN

Urban wastewater, as the main influent type of Waste Water Treatment Plants (WWTPs), has the characteristic of low carbon to nitrogen ratio (C/N). In the biological nitrogen removal (BNR) process, insufficient carbon source often affects the nitrogen removal efficiency and leads to more N2O emissions. We review recent researches on N2O emissions in the BNR process of wastewater with low C/N. The availability of carbon sources affects heterotrophic denitrification (HD) and autotrophic nitrification/denitrification processes, which are the main reasons for N2O emissions in BNR. For the sustainable development of BNR in WWTPs, we introduce strategies suitable for reducing N2O emissions in the BNR process of low C/N wastewater from two aspects: traditional process innovation and new process development. These strategies mainly include carbon source addition, adjustment of aeration strategy, optimization of oxidation ditch and biofilm facilities, and application of Anammox related processes. In the future, it is still necessary to further deepen this research direction through the normalization of N2O emission quantification standards, exploration of N2O metabolism mechanisms, assessment of environmental effects of emission reduction strategies, and practical application of new processes.

18.
Environ Sci Pollut Res Int ; 30(44): 99454-99472, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37610547

RESUMEN

The water quality status, spatial and temporal change processes, and water environment improvement process of urban rivers are valuable lessons to be learned under the sustainable development strategy. This study aims to reveal the water environment improvement process of intensively developed urban rivers, elucidate the spatial and temporal distribution characteristics of major pollutants, and provide recommendations for their water environment management. Water quality data from eight monitoring sites (2007-2020) in the Longgang River basin in Shenzhen, China, and comprehensive pollution index method (CPI), modified comprehensive pollution index method (M-CPI), and Pearson correlation analysis method were used for comprehensive analysis. The study shows that TN, TP, NH3-N, and COD have the greatest influence on the water quality of Longgang River, with the average pollution contribution of 53.39%, 14.49%, 11.66%, and 4.92%, in order. In 2015-2020, the water quality of the main stream of the Longgang River in the wet season was worse than that in the dry season, while the water quality of the tributaries Dingshan River and the Huangsha River in the dry season was worse than the wet season. The spatial distribution characteristics based on M-CPI indicate that the water quality of the lower reaches of Longgang River, the tributaries Dingshan River and Huangsha River, is relatively poor. In addition, the water environment improvement process of Longgang River can be divided into 3 stages: engineering stage (2007-2013, rating changed from heavily polluted to basically qualified), bottleneck stage (2013-2017, rating fluctuated slightly above and below basically qualified), and ecological restoration stage (2017-2020, rating reached qualified in 2019).


Asunto(s)
Contaminantes Químicos del Agua , Calidad del Agua , Monitoreo del Ambiente/métodos , Contaminantes Químicos del Agua/análisis , Ríos , China
19.
Water Res ; 238: 119993, 2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37146395

RESUMEN

Free nitrous acid (FNA) has been widely employed for improvement of wastewater management by altering sludge characteristic and function based on its polymer lysing and biocidal capacity. Sludge characteristic and function are commonly considered as the joint consequence of microbial individual behaviors and quorum sensing (QS) involved collective behaviours, but the role of the latter in FNA treatment was still as-yet-unidentified and addressed in this research. The results of sludge morphology and component characterized FNA-induced zoogloea deformation, including inner cell exposure, half of extracellular polymeric substances (EPS) reduction and adsorption site depletion. During zoogloea deformation, four acyl-homoserine lactones (AHLs), including C4-HSL, C8-HSL, C10-HSL and C12-HSL, transferred inward of microbiota, and their total contents reduced by 66% because of depressed signal production, augmented decomposer and recognition. Transcriptome analysis revealed that differentially expressed QS driven by AHL redistribution facilitated microbiota acclimatization including cellular motility and hydrolase synthesis for EPS consumption. Boosted motility may favor escaping from stress spot and moderating intercellular acidity based on cell motility test. Feasible EPS consumption provided nutrition for heterotrophic metabolisms testified by pure culture with EPS as sole nutrition. Our work thus comprehensively revealed QS behaviours responding to FNA and deepened the understanding to FNA treatment performance in wastewater management.


Asunto(s)
Microbiota , Zoogloea , Percepción de Quorum , Aguas del Alcantarillado , Aguas Residuales , Ácido Nitroso , Zoogloea/metabolismo , Acil-Butirolactonas/análisis , Acil-Butirolactonas/metabolismo
20.
Sci Total Environ ; 894: 164784, 2023 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-37302613

RESUMEN

The impacts of sulfide on biological nitrogen removal have been investigated repeatedly, but the impacts in terms of the removal technologies have not been systematically organized and discussed yet. This review recapped the dual character of sulfide in novel biological nitrogen removal and proposed the coupling mechanisms of nitrogen removal and sulfide interaction. The dual character of sulfide was basically divided into the advantage as electron donors and the disadvantage as cytotoxic agent to wide bacteria. The positive character of sulfide has been utilized for improving the performances of denitrification and anaerobic ammonium oxidation in laboratory and polit scales. Intriguingly, the sulfide cytotoxicity was feasibly turned into the profit which was to trigger the partial nitrification by selectively inhibiting ammonia oxidizing bacteria and nitrite oxidizing bacteria. Thus, this productive conversion dramatically promoted the importance of sulfide in sewage treatment. In order to maximize the favorable aspect of sulfide utilization, it was crucial to manage the sulfide concentration for fear of the side reactions with untargeted substances. Furthermore, S/N ratio in sewage may be the keystone that decides if sulfide benefits biological nitrogen removal. In sum, our work can facilitate the dialectical development of effective strategies for sulfide utilization in biological nitrogen removal.


Asunto(s)
Desnitrificación , Aguas del Alcantarillado , Aguas del Alcantarillado/microbiología , Nitrógeno , Electrones , Reactores Biológicos/microbiología , Nitrificación , Bacterias , Sulfuros , Oxidación-Reducción
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